Percussive tool.



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u UNITED STATES PATENTQFFICE f HEINRICH CHRISTIAN HANSEL, 0T GIESSEN, 0mm.

YEBCUSSIVE TOOL.

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Be it known that I, Hnnviiicn Ormisrnuv Hanser., a subject of the German Emperor, and resident of Giessen, Gorman have invented.a certain new and usefu Improvement in Percussive Tools, of which the following is a specification.

This invention ielat to a rcussivedrill having a resilient action, t e hammer or piston of which is operated by lazy tongs which slide over one or more levers and press these back against the ressure of springs under the action of the low. The forward movement of these lazv tongs is effected by an eccentric mount within a frame, the operative surface of which ecv-zis centric is inclosed at both sides by the straight operative surfaces of the frame.

The advantage of this invention resides in this, that the lazy tongs first' transmit the blow as a rigid inte er to the hammer and then yield toward t e end of the stroke; the strain on the springs is considerably reduced by the lever transmission, and in consequence there is much less danger of them breaking.

The arrangement of the eccentric within a frame inclosing its operative surface on two sides has the advantage that the frame is retracted positively by the eccentric, the

rings being the'reby relieved; the formation of the operative surfaces of the frame as plane faces reduces the friction between them and the eccentric.

In the acompanyin drawing which illustrates the invention, igure '1 is a longitudinal section on the hne A-B of Fig. 2, and Fig. 2 is a transverse section on the line In the neck of the drill casing b is guided the hammer or-piston d, having a reduced end d to engage the bit D. A shaft lu1 mounted in the casing b, and receiving. its motion form a motor of any suitable kind, for example an electric motor and aliexible connecting shaft, carries an eccentric a arran within a frame c. This frame is gui ed on the shaft a* by means of slots cx and surrounds the o rative face of the eccentric, allowing slight play between the two plane surfaces. Between the frame o and the hammer d is provided-and connected with each by a link--an arrangement of la tongs which consist of members f ivotdlly connected with one another by ta g to form a toggle and held between Specification et Lettera Intent.

Application led latch l, 1910. Serial In. 548,841.

Patented' Auna, '1910. l

levers ivotally mounted in the machine i casing a h1. A the ends of these levers, by means of spiral rings, are pressed bolts i mounted in s 'ets in the casin b. A collar on the bolt i and a cap on .t e socket serve as abutments to the spring; the springs tend to move the levers 7i into the sition shown in Fig. 1. The tension of t e springscan-,heregulated by 'thexcapflcas desired'. f'f* The .operation ofjthe drill' is a'sfollows If the shaft ci, whichv is .preferably provided with a ily-wheel m rotated in the direction of the arrow the eccentric a moves' the frame c and so forces the'lazy-tongs or toggle f and the hammer d against the bit Z. In consequence of the power of the springs, the lazy tongs at irst remain in he osition shown in Fi 1 and transmit the lcv.' to the bit as a rigid integer. We. the 'ra'ist-` ance oft'hpbit on further @wel moveiiit'gainstmcorinelikex, an `the evera e w 1c a-, a, on mm a certaziyn-tfngdu/Jli, lgs lazy-tongs are pressed together against the action of the springs, and the remaining part of the blow is transmitted through re-A f silient connections. When the eccentric has ne beyond the. forward stroke osition, the e c is positively retracted, t reversal being simtg ilied by the slight sFlay of the eccentric erein. Simultaneou y the hammer d and lazy-ton f also move backward the latter under t e action of the s springs, into their imtial positions, an the members of the lazy tongs arrangement again asume their normal position asshown mig.. The tension of the sprin is adjusted accordin to the hardness the rock or the like to drilled; the length of the lever arm f.,- is so arranged that the springs at each stroke are only pressed back avery small amounta few millimeters or a fraction of a millimeter-and in consequence are not likely to be fractured. 1" As is evident,'the form of the lazytongs and the levers as also their relative positions, maybevaried.

I claim: i l f ter 4de- 1. In apparatus of the cha scribed, acasing, a reci rocatory hammer, a

toggle connected tosai hammeneineans to move said toggle, swinging levirs to engage. said toggle, and means to yieidinly o dei... said levers in engagement with sai toggle.

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